International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 6 340 - 345 ______Design and Analysis of Antiroll Bars for Automotive Application

Mr. Khartode Ankush .N Prof. Gaikwad. Mahendra. U ME [Mechanical (Design Engineering)] DGOIFOE Swami- ME [Mechanical (Design Engineering)] DGOIFOE Swami- Chincholi Daund India Chincholi Daund India E-mail:[email protected] E-mail: [email protected]

Abstract-Anti-roll bar, stabilizer or sway bar, is a rod or tube, usually made of steel, that connects the left and right wheels members together to resist roll or swaying of the vehicle which occurs during cornering or due to road irregularities. An anti-roll bar improves the handling of a vehicle by increasing stability during cornering or evasive manoeuvres. The bar's tensional stiffness (resistance to twist) determines its ability to reduce body roll, and is named as “shear stress or Rolling Stiffness”. More vehicles have front anti-roll bars. Anti-roll bars at both the front and the rear wheels can reduce roll further. The other function of anti-roll bars is to tune the handling balance of a car. Under steer or overseer behaviour can be tuned out by changing the proportion of the total rolling stiffness that comes from the front and rear axles. The stabilizer bars contribute thus considerably to the improvement of comfort of the motor vehicles.

Keywords-Anti-sway bar, stabilizer bar, tensional angle, ,FEA, Automotive Design, Stress Analysis, Torsion Stiffness, Anti Roll Bar, Design Parameters, Bushing position, Rolling stiffness, Deflection. ______*****______

I. INTRODUCTION A typical anti-roll bar is shown in Figure 1.1 Introduction to Anti-roll bar 1.1information. First, the anti-roll shear stress of the bar has Anti-roll bar, sway bar, is a rod or tube, usually made of direct effect on the handling characteristics of a vehicle. steel, that connects the right and left of the vehicle which The main goal of using anti-roll bar is to reduce the occurs during turning. The bar's torsion stiffness (resistance vehicle roll. Body roll occurs when a vehicle deviates from to twist) decides its ability to eliminate body roll, and is straight-line motion. The line joining the roll centres of named as “shear stress or Rolling (SSOR) Stiffness”. An wheels suspensions forms the roll axis of a body. Centre of anti-roll bar improves the handling of a vehicle by gravity of a vehicle is generally above this roll axis. Thus, increasing capacity during cornering or evasive manoeuvres. while turning the centrifugal force creates a roll moment More vehicles have front Anti-roll bars. Anti-roll bars at about the roll axis, which is equal to the develop centrifugal both wheels can reduce rolling further. Properly chosen (and force with the distance between the roll axis and the CG. installed), anti-roll bars will reduce vehicle roll, that in turns Anti-roll bars serve two or more key functions. First they leads to good handling and increased driver confidence. A reduce roll of body, as explained above, and second provide spring rate increase in the front or rear anti-roll bar will a way to again spreading cornering loads between the both produce under-steer effect while a spring rate increase in the wheels, which in turns, given the capability of modify rear bar will develop uncontrolled steer effect. Thus, sway handling characteristics of the vehicle. bars are also used to improve directional control and stability. One more benefit of that, it improves traction by 1.2 Principles: limiting the camber angle change caused by body roll. Anti- Anti-roll bar is also a torsion spring that resists body roll bars may have not regular shapes to get around chassis roll motions. It is usually constructed out of a steel bar, components, or may be much simpler depending on the car. formed into a "U" shape that join to the body at two points, There are two possible facts to be considered about the sway and at the both sides of the suspension. If the both wheels bars within the presented and second, the geometry of the move together, the bar rotates about its mounting points. bar is dependent on the shape of other chassis components, When the wheels move relative to each other, anti-roll bar is the anti-roll bar is a rod or tube that connects the right and subjected to torsion and forced to roll. Each end of the bar is left spring connected to last link through a movable joint. The sway bar Members. It is used in front suspension, rear suspension or end link join in turn to a spot near a wheel or axle, in both suspensions; don’t matter the suspensions is rigid transferring forces from a maximum loaded axle to opposite axle type or independent type. side. Due to that forces are transferred: 1. from the maximum-loaded axle 2. To the jointed last link via a bushing 3. To the anti-roll (torsion) bar via a Flexible joint 4. To the jointed end link on the opposite side of the body 5. To the opposite axle. Figure 1.1 Anti roll bars with control Arm The bar resists the torsion through its shear stress. The stiffness or shear stress of an sway bar is proportional to the

340 IJRITCC | June 2016, Available @ http://www.ijritcc.org ______International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 6 340 - 345 ______stiffness of the material, the 4thpower of its radius, and the roll axis, which is equal to the product of centrifugal force inverse of the length of the arms(lever) (i.e., the shorter the with the distance between the roll axis and the (CG) centre arm(lever), the stiffness of bar is high). Stiffness is related to of gravity. This moment causes the inner suspension to the geometry of the mounting points and rigidity of the bar’s extend and to compress the outer suspension, thus the body sway. The increases stiffness of the bar, the more force roll occurs. required to move the wheels relative to both. This increases the amount of shear stress required to make the body roll. 1.6 Purpose and Operation In a turn the spring mass of the vehicle's body produces An anti-sway or anti-roll bar is subjected to force each linear force at the centre of gravity (CG), proportional to side of the vehicle to lower, or rise, to similar heights, to linear acceleration. Because the centre of gravity is usually reduce the sideways tilting (roll) of the vehicle on sharp not on the roll axis, the linearly force creates a moment corners, or large bumps. With the bar removed, a vehicle's about the rolling axis that tends to roll the body. (The rolling wheels can tilt much larger distances (as shown by the SUV axis is a line that connects the rear and front roll centres image). Although there are many variations in design, a (SAEJ670e)). The moment is called the rolling couple. Roll common function is to force the cross wheel's shock- couple is resist by the suspension rolling stiffness, which is a absorber, spring or suspension rod to lower, or rise, to equal function of the spring rate of the vehicle's springs and of the level as the other wheel. In a rapid turn, a vehicle tends to anti-roll bars. The uses of anti-roll bars allows designers to drop closer onto the outer wheels, and the sway bar soon eliminate roll without making the suspension's springs forces the opposite wheels to usually get closer to the develop stiffness in the vertical plane, which allows develop vehicle. As a result, the vehicle tends to "hug" the road body control with less compromise of quality. One effect of closer in a fast turn, where all wheels are closer to the body lean, a typical suspension geometry, is positive camber chassis (body). After the fast turn, then the downward on the outside of the turn and negative on the inside, which pressure is reduced, and the paired wheels can return to their reduces their cornering grip (specific with cross ply tires). normally height against the vehicle, kept at similar levels by the connecting sway bar.

Figure 1.2.1Basic Properties of Anti-Roll Bars

Figure 1.6.1SUV 1.5 Connections

Sway bars are connected to the other chassis (body) One way of estimating antiroll bar stiffness: components via 4 attachments. Two of these are the rubbers T=Vehicle track width (inches) bushings through which the sway bar is attached to the K=Fractional lever arm ratio (movement at rolls bar / frame. And the other two attachments are the fixtures movement at wheels) between the suspension members and the sway bar ends, d=Bar diameter (inches) either through the use of directly. R=Effective arm length (inches) L=Half-length of bar (Inch) S=Length of arm(lever) (inches) Q=Stiffness (lb*in per degree) Because each pair of wheels is cross-connected by anti-roll bar, the combined operation causes all wheels to generally offset the separate tilting of the others and the Figure 1.5.1Rubber bushings There are two major types of anti-roll bar bushings body tends to remain level against the general slope of the given according to the axial movement of the sway bar in terrain. A negative side-effect of joining pairs of wheels is the bushing. In both types, the bar is free to rotate in the that a bump to one wheel tends to also jar the opposite bushing. In the first bushing type, the sway bar is usually wheel, causing a big impact applied across the whole width free to move along bushing axis while the axis movement is of the vehicle. Other suspension techniques can delay or prevented in the second type. dampen this effect of the connecting bar, as if hitting small The bushing material is other important parameters. The holes that momentarily jolt a single wheel, whereas larger material of bushings is commonly rubber, nylon or holes or larger tilting then tugs the bar with the opposite polyurethane, but even metal bushings are used in some race wheel. cars. The main goal of using anti-roll bar is to reduce the body roll. Body roll occurs when a vehicle deviates from 1.7 Main Functions straight-line motion. Centre of gravity of a vehicle is Anti-roll bars provide 2 main functions. The first normally above this roll axis. Thus, while turning the function is the eliminate of body lean. The reduction of body centrifugal force creates a roll (swing) moment about the lean is dependent on the total rolling stiffness of the vehicle. 341 IJRITCC | June 2016, Available @ http://www.ijritcc.org ______International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 6 340 - 345 ______Increasing the total rolling stiffness of a vehicle does not bodyrolling by resisting any un-even vertical motion change the steady state total load (weight, mass) transfer between the pair of wheels right and left suffer from fatigue from the inside to the outside wheels, it only reduces body and tough failure. In this study, several structural analyses of lean. The total lateral load transfer is determined by the an anti-roll bar of passenger car were carried out by means Centre of Gravity height and track width. Other function of of finite element (FEA) technique to determine stress anti-roll bars is to tune the driving balance of a car. Steering distributions and torsion stiffness (shear stress). The results behaviour can be tuned out by changing the proportion of of FEA analyses indicated that, there is difference [3] the total rolling stiffness that comes from the front and rear axles. Increasing the proportion of roll stiffness at the front P. M. Bora1, Dr. P. K. Sharma2,The aim of this paper increases the proportion of the total load (weight) transfer is to report the analysis of Vehicle anti-roll bars (stabilizer that the front axle reacts to and decreases the proportion that bars)used for suspension components limiting body roll the rear axle reacts to. In general, this makes the outer front angle using the finite element analysis tool ANSYS. Vehicle wheel run at a comparatively higher slip angle, and the outer anti-roll bars have a direct effect on the handling rear wheel to run at a comparatively low slip angle, which is characteristics of the vehicle. Ride comfort, handling and an under steer effect. Increasing the proportion of roll road holding are the three aspects that a vehicle suspension stiffness at the back axle has the opposite effect and system has to provide compromise solutions. type of end decreases under steer. connection final anti-roll bar properties are estimated at The function of stabilizer bars in motor vehicles is to varying load.[4] reduce the body roll during cornering. The body roll is influenced by the occurring wheel load (weight) shift and Dariusz Bojczuk, Anna Rębosz-Kurdek, The problem the change of camber angle. of maximization of the buckling load and the problem of maximization of the natural vibration frequency under or II. LITERATURE REVIEWS over a condition imposed on the global cost is discussed. Prof. Laxminarayan Sidram Kanna1, Prof. S. V. Cross-sectional areas of sway bar structures and number of Tare2,Properly chosen (and installed), stability bar will elastic and plastic supports, their positions and stiffnesses reduce body roll, which in turns leads to good handling and (or the number and positions of rigid (tough) supports) are increased driver confidence. Stability bar analyses in the selected as design parameters. The proposed here algorithm past were performed using analytical methods. In general, of optimization of bar structures with their supports and this good stability bar analyses are multi-disciplinary, helps is applied for analysis of some optimization including calculations related to the stresses. Failures such problems.[5] as like wear or scoring. In this trying to design stability bar to resist external force or bending, shear failure. As MPravin Bharane, Mr. Kshitijit Tanpure,The computers have become higher or more powerful, people objective of this paper is to analyze the main or good have direction to use numerical reaches to develop geometric parameter which affects rolling stiffness of Anti- theoretical models to predict the purpose of whatever is Roll bar. By the optimization of good geometric parameter, studied. This has improved stability bar analyses and we can increase or develop the rolling stiffness and reduce computer simulations. Numerical (FEA) methods can the mass of the bar. Changes in design of anti- roll bars are potentially provide more accurate solutions since they quite common at various or long area steps of vehicle normally require much less restrictive assumptions. [1] production and a design analysis must be performed for each change.. Locating the bushings closer to the center of the bar Cristiano Antonio de Andrade1, André Chaves de increases the stresses at the bushing locations which results Jesus2, It was obtained the mechanical properties in in rolling stiffness of the bar decreases and the max Von hardness of the sway bar material. The structure was mises stresses increases.[6] characterized by optical microscopy. The observation microstructures were ferrite,partite. The steel used in the bar Manoj Purohit, Shailesh Kadre, This paper presents (stabilizer) has been classified by chemical and analytical an approach of FEA and correlation of the results with the analysis as SAE 1045. The analytical calculation of the test results and helps the design to move to the next level of stresses and stiffness acting at critical points of the sway bar concept quickly. The approach includes the [7] was performed to check the displacement range that the bar (stabilizer) support without reaching the yield strength of the P.Senapathi, S.Shamasundar, G. Venugopala Rao material. Occurs on both sides of the bar, being result of the and B.M.Sachin, Durability of automobile stabilizer bar is folding process used. [2] assessed in the present study. Finite element analysis of the bar (stabilizer) is performed based on the experimental Husen J. Nadaf Prof. A. M. Naniwadekar, All observations. Fatigue analysis is performed under and over suspension systems have a common goal, which is to cyclic loading. Effect of shot peening have been taken into develop the ride in terms of comfort, handling, and safety. account. Fatigue cycles are defined for the maximum This is accomplished by influencing the motions affected by loading conditions. Custom built fatigue testing equipment road irregularities (bad) to the wheels and axles while is used to simulate the fatigue life of [8] minimizing their effect on the vehicle body and frame (body). Sway bars used in ground vehicle to reduce

342 IJRITCC | June 2016, Available @ http://www.ijritcc.org ______International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 6 340 - 345 ______III. PROBLEM DEFINITION The bar Max shear stress = T*R/J The stress field at the bar (stability) will be analyzed using a for 30 dia= Z= 174. 98 N/mm three-dimensional finite element (FEA) solid model. There for 31 dia= Z= 153.54 N/mm2 are two various important facts to be considered about the stability bar that first, the anti-rolling stiffness of the bar has for 32 dia= Z= 145.47 N/mm2 direct effect on the handling (turning) characteristics of a Design of Hollow stability bar: vehicle (body). And second, the geometry of the bar Shear stress of hollow bar with different diameter (stabilizer) is dependent on the geometry of other chassis For 30 dia= Z= 179.73 N/mm2 components. For 31 dia= Z= 162.42 N/mm2 For 32 dia= Z= 147.20 N/mm2 Here, the analysis of solid stability bar is carried out in three different cases, by considering, Solid bar with 30mm diameter,31mm and 32mm and correspondingly design calculations such as load acting, moment, torque transmitted, polar moment of inertia and shear stress has been calculated.

4.2 Analysis of hollow anti rolls bars in ANSYS (Numerical method) Figure 3.1 SUV

3.1 INPUT PARAMETERS INPUT PARAMETERS VALUES Cross-section type Solid Solid round cross- round cross-section section Section radius 15.5 mm Bushing type 1 Bushing locations ± 300 mm Bar material Alloy steel(chromium- molybdenum) Modulus of Elasticity 2.1x105Mpa

The loading is applied at point A, inward to or outward from plane of the page. The roll stiffness of such a bar can be Figure 4.2.1a (solid) calculated as: L= a+b+c (L: Half Track Length) fA =[(P(l13-a3) + (L/2 *(a+b)2) + (4l22 (b+c))/3EI ] (fA :- Deflection of point A) KR = (P*L2) / 2fA …….. KR: Roll Stiffness of the bar Max shear stress = T*R/J …….. T= Torque R= outer radius of bar J= Polar Modulus

IV. METHOLODOLOGY (ANALYTICAL METHOD)

4.1 Design of anti-roll bar Figure 4.2.2b (solid) 1) On the basis of comparative shear stress of solid and hollow anti-roll bar of different diameter This chapter deals with the analytical analysis of stability bar, where design equations are developed and calculation of load acting, moment, torque transmitted, polar moment of inertia has been calculated. However the following points discuss the same. 4.1.1Design of solid stability bar 4.1.2Design of hollow stability bar Let us discuss the points one by one:

Design of solid stability bar: Shear stress of solid bar with different diameter Figure 4.2.3c (solid)

343 IJRITCC | June 2016, Available @ http://www.ijritcc.org ______International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 6 340 - 345 ______V.RESULTS & DISSCUSSION After extensive study it has been observed that shear stress is predominant in the analysis of stability bar. Also it has been observed that by varying the dimensions for solid and hollow the shear stress goes on decreasing, the following table shows the same.

5.1ANALYTICAL RESULT Dimensions Solid Stability bar Hollow stability (shear Stress) bar(shear

Figure 4.2.4d (Hollow) (N/mm2) Stress)(N/mm2) For 30 mm 174.98 179.73 For 31mm 153.54 162.42 For 32mm 145.47 147.20 5.2 NUMERICAL RESULT (ANSYS) Dimensions Solid Stability bar Hollow stability (Shear Stress) bar(shear (N/mm2) Stress)(N/mm2) For 30 mm 173. 98 178.73 For 31mm 152.54 160.42 For 32mm 144.47 146.20 Figure 4.2.5e (Hollow)

There is 0.1 % difference between mathematical and numerical results It has been observed from the above table that, for same dimensions the rate of shear stress is maximum for hollow stability bar. It is also interesting to note down the point that, the rate of shear stress is goes on decreasing as the dimensions increases for both the cases of solid and hollow stability bar. It can be discussed from the above table; there is considerable Percentage increase in shear stress for hollow stability bar as compared with solid bar.

Figure 4.2.6f (Hollow) Also this rate of percentage will goes on reducing as the dimensions are increased from 30mm to 32mm. Table 4.1INPUT PARAMETERS INPUT PARAMETERS VALUES VI.CONCLUSIONS Cross-section type Solid round Solid round cross- 1) Parametric optimization obtaining reduction in stress at cross-section section corner bends stabilizer bar 2) It is important that the target weight reduction is greater Section radius 15.5 mm than 60 to70 % of the weight of comparable solid stabilizer Bushing type 1 bar. Bushing locations ± 300 mm 3) Increases stiffness with diameter Bar material Alloy steel(chromium- 4) Increases shear stress with diameter molybdenum) 5 5) By increasing the bushing stiffness or shear stress of Modulus of Elasticity 2.1x10 Mpa Anti-roll bar, increases Anti- roll stiffness, also increasing the stresses induce in the bar 4.3 Comparison between max. Prin. Stress, for different 6) A stability bar improves the handling of a vehicle by diameter: increasing stability during cornering or evasive manoeuvres. The bar Max shear stress = T*R/J Conveniently chosen (and installed), stability bar will for 30 dia= Z= 173. 98 N/mm reduce body roll, that in turns leads to good handling and for 31 dia= Z= 152.54 N/mm2 increased driver confidence. for 32 dia= Z= 144.47 N/mm2 REFERENCES Design of Hollow stability bar: [1] Prof. laxminarayansidram kanna1, prof. s. v. Stare2 Shear stress of hollow bar with different diameter feasibility of hallow stability bariosr journal of For 30 dia= Z= 178.73 N/mm2 mechanical and civil engineering (iosr-jmce) e-issn: 2278-1684, p-issn: 2320-334x pp 76-80 For 31 dia= Z= 160.42 N/mm2 [2] Cristiano antonio de andrade1, andréchaves de jesus2, For 32 dia= Z= 146.20 N/mm2 stress analysis at the critical points of astabilizer bar vol. 4 no. 6 august, 2015 344 IJRITCC | June 2016, Available @ http://www.ijritcc.org ______International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 4 Issue: 6 340 - 345 ______[3] Husen j. nadaf prof. a. m. naniwadekar,p. m. bora1, dr. p. k. sharma2 analysis of anti-roll bar of passenger car for its nonlinear behavior with help of caeIJSTE - International Journal of Science Technology & Engineering | Volume 2 | Issue 01 | July 2015 ISSN (online): 2349-784X [4] P. M. Bora1, dr. p. k. sharma2 vehicle anti-roll bar international journal of advanced technology in engineering and science www.ijates.com volume no.02, issue no. 07, july2014 issn (online): 2348 – 7550 analyzed using fea tool ansys [5] Dariuszbojczuk, annarębosz-kurdekoptimal design of bar structures with their supportsin problems of stability and free vibrationsBjournal of theoreticaland applied mechanics 52, 2, pp. 533-546, warsaw 2014 [6] Pravinbharane, mr.kshitijittanpure, design, analysis and optimization of anti-roll barpravinbharaneet al. int. journal of engineering research and applications www.ijera.com issn : 2248-9622, vol. 4, issue 9( version 4), september 2014, pp.137-140 [7] Manoj purohit, shaileshkadreanalysis of stabilizer bar using simplified approach. [8] P.Senapathi, s.shamasundar, g. venugopalarao and b.m.sachin, endurance testing and fe analysis of four wheeler automobile stabilizer barpresented at toptechsae and arai, feb, 2009. Due for publication in journal of fatigue.

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